| Message ID | 118f28ccb9be59c72f4c7a2a0ce3c8591dea6582.1503277387.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | da74f659205ea08cb0fd0b3050637b0e0eb31520 |
| Headers | show |
On Wed, 2017-08-23 at 14:54:32 UTC, Christophe Leroy wrote: > Commit 694fc88ce271f ("powerpc/string: Implement optimized > memset variants") added memset16(), memset32() and memset64() > for the 64 bits PPC. > > On 32 bits, memset64() is not relevant, and as shown below, > the generic version of memset32() gives a good code, so only > memset16() is candidate for an optimised version. > > 000009c0 <memset32>: > 9c0: 2c 05 00 00 cmpwi r5,0 > 9c4: 39 23 ff fc addi r9,r3,-4 > 9c8: 4d 82 00 20 beqlr > 9cc: 7c a9 03 a6 mtctr r5 > 9d0: 94 89 00 04 stwu r4,4(r9) > 9d4: 42 00 ff fc bdnz 9d0 <memset32+0x10> > 9d8: 4e 80 00 20 blr > > The last part of memset() handling the not 4-bytes multiples > operates on bytes, making it unsuitable for handling word without > modification. As it would increase memset() complexity, it is > better to implement memset16() from scratch. In addition it > has the advantage of allowing a more optimised memset16() than what > we would have by using the memset() function. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/da74f659205ea08cb0fd0b3050637b cheers
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h index b0e82466d4e8..b9f54bb34db6 100644 --- a/arch/powerpc/include/asm/string.h +++ b/arch/powerpc/include/asm/string.h @@ -10,6 +10,7 @@ #define __HAVE_ARCH_MEMMOVE #define __HAVE_ARCH_MEMCMP #define __HAVE_ARCH_MEMCHR +#define __HAVE_ARCH_MEMSET16 extern char * strcpy(char *,const char *); extern char * strncpy(char *,const char *, __kernel_size_t); @@ -24,7 +25,6 @@ extern int memcmp(const void *,const void *,__kernel_size_t); extern void * memchr(const void *,int,__kernel_size_t); #ifdef CONFIG_PPC64 -#define __HAVE_ARCH_MEMSET16 #define __HAVE_ARCH_MEMSET32 #define __HAVE_ARCH_MEMSET64 @@ -46,6 +46,8 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n) { return __memset64(p, v, n * 8); } +#else +extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); #endif #endif /* __KERNEL__ */ diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S index 8aedbb5f4b86..a14d4df2ebc9 100644 --- a/arch/powerpc/lib/copy_32.S +++ b/arch/powerpc/lib/copy_32.S @@ -67,6 +67,20 @@ CACHELINE_BYTES = L1_CACHE_BYTES LG_CACHELINE_BYTES = L1_CACHE_SHIFT CACHELINE_MASK = (L1_CACHE_BYTES-1) +_GLOBAL(memset16) + rlwinm. r0 ,r5, 31, 1, 31 + addi r6, r3, -4 + beq- 2f + rlwimi r4 ,r4 ,16 ,0 ,15 + mtctr r0 +1: stwu r4, 4(r6) + bdnz 1b +2: andi. r0, r5, 1 + beqlr + sth r4, 4(r6) + blr +EXPORT_SYMBOL(memset16) + /* * Use dcbz on the complete cache lines in the destination * to set them to zero. This requires that the destination
Commit 694fc88ce271f ("powerpc/string: Implement optimized memset variants") added memset16(), memset32() and memset64() for the 64 bits PPC. On 32 bits, memset64() is not relevant, and as shown below, the generic version of memset32() gives a good code, so only memset16() is candidate for an optimised version. 000009c0 <memset32>: 9c0: 2c 05 00 00 cmpwi r5,0 9c4: 39 23 ff fc addi r9,r3,-4 9c8: 4d 82 00 20 beqlr 9cc: 7c a9 03 a6 mtctr r5 9d0: 94 89 00 04 stwu r4,4(r9) 9d4: 42 00 ff fc bdnz 9d0 <memset32+0x10> 9d8: 4e 80 00 20 blr The last part of memset() handling the not 4-bytes multiples operates on bytes, making it unsuitable for handling word without modification. As it would increase memset() complexity, it is better to implement memset16() from scratch. In addition it has the advantage of allowing a more optimised memset16() than what we would have by using the memset() function. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/string.h | 4 +++- arch/powerpc/lib/copy_32.S | 14 ++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-)